Current art building panels are typically manufactured in three layers: a concrete layer that faces to the outside of the building, a concrete layer that faces to the inside of the building and an insulation layer in between. Typical insulating materials that are used in these panels include polyisocyanurate or polystyrene loosely sandwiched between the two concrete layers. Typical R values for this type of a panel range between about 4/inch to about 8/inch.
The structures made of two layers of concrete and loose foam insulation generally have high compression strength, but lack tensile and shear strength. This makes the panels susceptible to delamination from shearing forces such as due to high winds. Concrete also has a tendency to crack or shatter from the impact of blunt force.
Heating or cooling losses resulting from the use of low insulation values of typical panels used in all buildings can be significant. It would be, therefore, be desirable to use building panels in all construction that have high insulation value in the range of about 30/inch to about 40/inch and even higher, yet have high compressive strength, tensile strength, shearing strength and bending rigidity to withstand high winds, withstand the high vertical loads exerted by roofs and floors, and maintain integrity while being hoisted, loaded onto trucks and transported.